Battery Problems

Hi guys!
So my Macbook's been acting weird lately.
The screen keeps going black while i'm working on it but when I plug it in it starts working again. I keep thinking the battery had ran out but when i check it still says it's in its 20%s.
Today the same thing happened again and when I went to plug it it the battery icon had an x on it. It said that it couldn't recognize the battery.
I shut my computer off, took out the battery and placed it again. When i turned the computer back on its working properly.

Any insights?

PS: i spilled orange juice on it about two months ago... the computer's been working fine, only that little problem. So i doubt the whole spill has anything to do with it..